For various types of accidents occurring in marine environments, ships are usually equipped with safety facilities and apparatuses which are required by the classification society rules and Safety Of Life At Sea (SOLAS).
Even with the preparation, there are still many accidents such as overturns or submergence, due to crashes or grounding, in the sea and damages of human lives, environments and property in the situation of hardly utilizing essential sailing equipment.
In a general case that there is inundation by a damage due to an overturn or grounding, a waterproofing work is performed to close inundated areas, for obstruct further inundation, by filling up broken parts or by utilizing watertight doors and partitions.
Under the areal closure, inundation at closed areas causes a trim and a heeling of a ship and eventually results in a serious list which disables operations of principal sailing equipment such as navigation radars or power generators.
Therefore, in the case that inundated areas of a ship are overrun beyond a controllable range of safety or watertight doors are out of order, unstable marine conditions gradually aggravates the disaster to deepen inundation, eventually causing the ship to be overturned or submerged.